Radioactive Iodine Therapy for Thyroid Cancer in India

Radioactive iodine (RAI), also called I-131 therapy, is a targeted treatment used after thyroid surgery for differentiated thyroid cancers, most commonly papillary and follicular thyroid cancer. It works because thyroid cells, including any that remain after surgery or have spread elsewhere in the body, naturally absorb iodine. The radioactive iodine, given as a swallowed capsule or liquid, is taken up specifically by these cells and destroys them from within, while sparing most other tissue in the body.

Why it is used after surgery

Even after a thorough thyroidectomy, small amounts of thyroid tissue can remain. RAI is used to destroy this remaining tissue (called remnant ablation), treat any cancer cells that may have spread to lymph nodes or elsewhere, and make future monitoring for recurrence more reliable, since any iodine-avid tissue detected later is more likely to represent a true recurrence rather than normal leftover tissue.

Preparing for treatment

Before RAI, thyroid-stimulating hormone (TSH) levels need to be raised, either by stopping thyroid hormone replacement medication for several weeks, which causes temporary hypothyroidism, or through injections of a synthetic TSH medication that avoids this. A low-iodine diet is usually followed for one to two weeks before treatment as well, since dietary iodine competes with the radioactive iodine for uptake by thyroid cells. Your care team will guide you through this preparation before your dose is scheduled.

Dose and isolation requirements

The dose given depends on your specific case: a lower dose for straightforward remnant ablation, and a higher therapeutic dose for cases with known spread beyond the thyroid bed. Higher doses require a short stay in a specially designed isolation room, due to radiation safety regulations, until radioactivity levels fall enough to be safe for others. Lower doses can often be given without hospital admission, following at-home precautions instead.

Safety precautions after treatment

After receiving radioactive iodine, patients are advised to limit close contact with others, particularly children and pregnant women, avoid sharing utensils, and sleep separately for a period ranging from a few days to about a week, depending on the dose received. Your care team gives you specific, written precautions tailored to your exact dose, since this affects how you plan your travel home.